Fumigating with ethylene bromide and methyl bromide



Patented Aug. 12, 1952 7 UN T D? ;STATE V 2,606,857" FUMIGATING WITH ETHYLENE BROMIDE d J ANDMETHYLBROMIDE W Joseph Carl Dawson, FergusomMo. N Drawing. Application January 11, 1951, Serial No. 205,613 5 Claims. (01. 167-39) This 111176111716? reit to'methods'of um atincreased ,by reason of the lack of odor of cerl and ore p fio lafly t 'm th ds for Space, tain fumigants. Furthermore. where fumigants bulkstorage and soil fumigation. are made up of several components it is often This application is 'a 'continuation-in-part of necessary to provide more than one compound my copen'ding application, Serial No. 37.567. filed 5 in a protective gas mask canister whereby the lflpril 14,1949, now abandoned. effectiveness of the mask is reduced considerably.

Briefly, this invention provides a method of Other objections to previous fumigants arise fumigating space, bulk storage or soil by means from their extreme volatility which brings about of a" mixture consisting essentially of ethylene dian explosion hazard in closed storage spaces and bromide and methyl bromide pe'r se or dissolved also augments the tendency oithe fumigant to in a carrier- The ethylene vdibromide -methyl escape from the storag region. Furthermore, bromide mixture constitutes notless, than apcritical proportions between the' various'compoproximately 50 %l or the composition. pents of various fumigantsrender them difiicult fhmon'g. the objects of this invention are the to adaption to special or. particular fumigation provision of anef fectivefumigantwhich is adaptproblems wher thereareoptimum vapor presabl' to all types of fumigation; the provision sure values inherent to the solution of the do .f umigant which'iseflective in relatively small problem. v x loentrations; the "provision 'of a fumigant It has been found that a f umigant comprising which affords efi'eotive results; and the provision a mixture of ethylene dibromide (also often called of improved methods of fumigation. Other feayl ne bromide and methylbrom e possesses tures will be in part apparent and inpar't pointed the desirable properties enumerated above and out hereinafter; is very effective in the varioususs of furni gants. The invention accordingly comprises the in- The mixture has a readily detectable and disgredients and combinations of ingredients, the tinctive odor which serves to warn the operator proportions thereof, steps and sequence of steps, of danger promptly upon exposure. Furtherfeatures 'Of composition and manipu more, protection against both compounds may w h exemphfied'm the methodsherebe had with a single-component gas mask caninafter-described, and the scope of .the applicaisten 3 99 of Whwh Wil1 beindicated While it is true thatbothethylene dibromide c aims.

and methyl bromide havebeen used separately 7 The n for fumigation in spacerbulk Storage as iumigants they have not been used-in comand soil is well known and'recognized. Many v V compounds have been Suggested and tried in con; bination. Furthermore,- the synergistic effect of motion with the fumi men 0 s combining the two --compounds has been clearly storage and 11, and 5 3 f g i ggi demonstrated in tests which establish that the ject criticismvand objection for one or more effectiveness of mixtures of the compounds is far ar large number f reasons It is an impor in excess of what might be predicted based upon tant'object of this mv t o provide a fumi observations made while using the components gating 'method "capable of overcomin th alone and separately; r v 1 advantages and objections of" previous fumigat- 40 Table I below shows the results, of tests made ing'compounds and methods; 3 to inveigate the synergistic action obtained by An' -important problem --in fumigating is the combining ethylene-dibromide and methyl brofactor of danger to the-operator which is often mlde to produce an improved fumigant.

, TABLE .I

Dosage'Mg. per liter 5 Mortality L ee i tfie th 1 a r I a r I After After CHgB1'.OHgBl- OHSBI 24Hours 48 Hours i 0 100.0 0 8.48 08.0 72.0 ".7 100.0 0 2.25 0 2.0 9.2 20. 9 79.1 2. 25 8. 48 99. 3 100. 0 0 100.0 0 I 0.75 25.9 33.7 100.0 0 4.50 0 8.0 22.5 40. 0 00. 0 4. 50 0. 07. 2 100. 0 0 100.0 0 5.02 14.8 23.3 5 100.0 0 5.02 0 20.3 47.9 50.0 50.0 5.02 5.02 91.9 100.0 -0 100.0 0 9.00 88.6 02.0 .100. 0 0 9. 00 0 27. 3 57. 3 25 75. 0 2. 25 0. 75 92. 0 100. 0 0 100.0 0 7.87 55.0 V 72.1 100.0 0 7.87, 0 24.8 05.1 28. 5 71. 5 2. 25 5. 02 88.0 100. 0

Q 1 Each value represents the mean of 5 replicates.

tainers and the percentage mortality determined at 2d and 48 hours after the beginning of the exposure period. The confused flour beetle,

Tribolium confusum, was used as a test insect for these investigations.

It wil be noted from Table I that the fumigants of this invention proved vastly superior to fumigan-ts consisting of either ethylene dibromide or methyl bromide alone. In every case, the fumigants made up of the combination of ethylene dibromide and methyl bromide produced a 100% kill in 48 hours. In contrast, neither the ethylene dibromide nor the methyl bromide ever eifected a 100% kill in a 18 hour period. The synergistic action of the combination is clearly established. In every case the effect of combining concentrations of the two components is to bring about amuch greater mortality than would be supposed or predicted from values obtained when using either component alone and far in exces of the figure obtained by} merely adding the mortality figures for the single components together. That this effect cannot be attributed merely to the presence of increased concentrations of fumigants whenever the mixture is used is clearly shown by the last two examples where the concentration of fumigant was heldconstant in all cases, and a synergistic effect is still obtained. Results such as illustrated by the examples have been repeatedly and consistently obtained.

The following examples illustrate the invention.

Example 1 A flour mill was fumigated. The mill consisted of a packing room and several rooms adjoining and adjacent thereto of wood frame construction, extremely open and likely to leak fumigant rapidly. Test; box. insects were used and methyl bromide was used as the fumigant. Part of the gas was shot into the area. to be fumigated and then after a reasonable time interval had passed, the area was thenchecked with a halide leak detector and found to contain only 'a trace of gas and the insects apparently were not affected. Additional gas was released and more time allowed to elapse whereupon a similar reexamination showed a similar condition. Gas was released then for a second time and similarly for a third time. The total amount of gas used amounted to 470 pounds which was approximately 2.21 pounds per thousand ,cubic feet. When aeration had been completed, the insect kill in the test boxes and elsewhere was about 50% Several months later the same flour mill was refumigated but a composition. of methyl bromide and ethylene dibromide was employed. Sixtyfive pounds of ethylene dibromide were p oured Example 2.

A flour warehouse of'open structure similar to that of Example 1 was fumigated. Eighty percent methyl bromide and 20% ethylene dibromide by weight were mixed together. The mixed vapor Was then released into the area.

, Again a 100% kill of the insects was obtained.

Example 3 A mill and warehouse were fumigated. The warehouse has one fioor which is constructed of wood and covered with corrugated metal. This. building has a content of 141,751 cubic feet. The mill is constructed of brick and consists of a basement, cupola and three floors. The content is 170,700 cubic feet. The packing department is a separate building consisting of two floors and a basement with a content of 37,060 cubic feet.

The mill properincluding the feeddepartment obtaining a kill w'ouldtbe most difficult. Al-

though the warehouse is looselyconstructed; a. substantially complete kill was obtained.

Example 4 t Twocircular steel grainbins containing 3000 bushels of corn each were fumigated on a clear, rather windy, moderately warm day. liifteenpounds per binof a. mixture of 80%. methyl.

7 bromide and 20% ethylene dibromide were. em-

was buried just'a. few inches. below. the surface.

and the other bag approximatelytwo and onehalf feet. below the surfaceof. the cor-n. Iii-the center of each bin a probe containingcorn with the immature stages and adults of Sitophilus granarius (L.) and Tribolium confusum was buried. These corn samples in the probes were approximately two feet apart from the bottom of the bin to thesurface of the corn inside the bin.

. Fumigation was performed by burying a Saran tube approximately ten to fifteen inches below the surface of the corn in one complete circle approximately three feet from the side of the bin.

. The tube was plugged at one end and small holes .were drilled at every three foot interval in the sure. The gas was released by opening a valve to expel the desired amount of gas.

Test insects were removed ten days later for observation.

The results obtained were as follows: 1 g bromideiand ethylene. wdibromide should not con- Pcrcent Mortalityiof Teatmentanddosa e I I Bin Number 1000 bu; m g. Srtophtlus grcnarrus (L). iZlrtbch/um confnsum Percent :Percent Percent Percent Percent Percent 100 I 100 100 100 100 100" 100 i i 100 100. .100 100 4 100 j. a

Subsequent emergence of immature stages of stitute substantially less than 50% of the total Sitophilus granarius (L.) and of Sitotroya of the composition. Other'customary carriers in cerealella Oliv. from infested corn samples buried which the mixture is solubleimay be utilized in in the bin was practically zero. l uio'f he low, bo petreleumire'ctionr V Emmple 5 Animportantadvantageof'the retention ofthe V V a synergistic efie'ctup'on combining ethylene di- Example 4 was repeated but in lieu of a mixture bromide and methyl bromide in any proportions of 80% methyl bromide and 20% ethylene dilies in the fact that this permitsthe adjusting bromide, a mixture of methyl bromide'and of the vapor pressure to meet any particular re- 50% ethylene dibromide by weight was employed. quirements set up by a specific fumigating prob- The results were as follows: lem. That such different requirements do exist Percent Mortality of- Bm Number ggg gfi gggf Se'topbtlus granarius (L.) Trtbotium confnsumi 3and6 9 l2and 3and6 9 l2and Ft. 15 Ft. Ft. '15 Ft.

Percent Percent Percent Percent Percent Percent 50% E. D. B1. 100 100 100 100 100 100 2 M. Br. 50% E. D. Br. 50%.--. 100 100 100 100 100 100 Subsequent emergence of immature stages of as between soil fumigation and space fumigation, Sztophz'lus granarz'us (L.) and of Sitotroga for example, is well known and recognized in the cerealella Oliv. from infested corn samples buried art. in the bin was practically zero. Although all proportions of the components of Example 6 40 the fumigant or this invention containing between 5 and 95% ethylene dibromide are believed ple 4 was rep d except that while one to possess desirable synergistic properties, the bin contained 3000 bushels of com the second bin preferred range of mixture is defined by fumicontained approximately 2000 bushels, and in lieu gants containing from about 20% to about 80% of a mixtur f m yl bromi and 2 ethylene dibromide with the remainder essentially ethylene dibromide, a mixture of 20% methyl al1 methyl bromide.

bromide and 80% ethylene dibromide by weight In view of the above, it will be seen that the was employed. several objects of the invention are achieved and The results were as follows: other advantageous results attained.

Percent Mortality 01'- Bin Number gg gag Sttophtlus granariue (L) Trtbottum conj'nsum Bandfi 9, 12 and 3 andG 9, 12 an Ft. 1:; Ft. Ft. 15 Ft.

Percent Percent Percent Percent Percent Percent 1 M. Br. 20% E D. Br. 80%--.- v100 V 100 100 100 100 100 2 M. Br. 20% E D. Br.s0%- 100 100 100 100 Subsequent emergence of immature stages of As many changes could be made in the above Sitophz'lus gmnarius (L.) and Sitotroga. cerealella methods without departing from the scope of the Oliv. from infested corn samples buried in the bin invention, it is intended that all matter contained was practically zero. in the above description shall be interpreted as Had grain fumigant materials now commonly illustrative and not in a limiting sense.

employed been used in carrying out the fumiga- I claim:

tion described in Examples 4, 5 and 6, the custo- 1. The method of fumigating which comprises mary amount would have been 55 pounds per treating insect infested material and space witha thousand bushels.

vaporized mixture of between approximately 5% Where S011 fumigation is to be carried out, the and approximately by weight of ethylene mixture of methyl bromide and ethylene didibromide and between approxim y and bromide may be dissolved in a suitable carrier approximately 95% by weight or methyl bromide. such as a low boiling petroleum fraction. In such 2. The method of fumigating which comprises compositions, however, the mixture of methyl treating insect infested material and space wltha vaporized mixture of between approximately 20% and apprommately'80% by weightof ethylene dibromide and between approximately 80% and approximately 20% by weight of methyl bromide.

3. The method of fumigating which comprises treating insect infested materialand; space with a vaporized mixture of methyl bromideand ethylene dibromide, said mixture comprising between ap weight of ethylene dibromide and approximately 15 80% by weight of methylbromide.

5. The methodof fumigati'ng which comprises treating insect infested material and space with a vaporized mixture of methyl bromide and ethylene dibromide in essentially equal proportions.

Y JOSEPH CARL DAWSON;

REFERENCES CITE?) The following referencesare of rec'ordin the file of this patent:

UNITED STATES PATENTS -Number Name Date 2,147,947 Johnson Feb. 21, 1939 2,324,471 Allen et a1. July 20, 1943 2,324,472 Allen et a1. July 20, 194 2,344,105 Peters July 21),"1943 2,362,472 Dreisbachet a1. Nov. 14, 1944 2,391,890 l Fletcher et al. 'Jan. 1, 1946 2,425,238 Fletcher et a1. Aug. 5,. 1947 FOREIGN PATENTS Number Country Date 219,013 Switzerland -1 Mar, 1, 1942 273,713 Great Britain Oct. 6; 1927 453,084 Great Britain Sept. 4, 1936 571,693 Germany Apr. 29, 1930 OTHER REFERENCES Huckel ett al. J. Prak-t. Chem volume 142,. pages 207' to 217' (1935). 

1. THE METHOD OF FUMIGATING WHICH COMRPISES TREATING INSECT INFESTED MATERIAL AND SPACED WITH A VAPORIZED MIXTURE OF BETWEEN APPROXIMATELY 5% AND APPROXIMATELY 95% BY WEIGHT OF ETHYLENE DIBROMIDE AND BETWEEN APPROXIMATELY 5% AND APPROMIMATELY 95% BY WEIGHT OF METHYL BROMIDE. 